Thomas huntington and ferdinand heberlein



UNTTnn STATES PATENT O FFTCE.

THOMAS HUNTINGTON AND FERDINAND HEBERLEIN, OF PERTUSOLA, ITALY.

PROCESS OF TREATING SULFID ORES OF LEAD, &c., PREPARATORY T0 SMELTING.

SPECIFICATION forming part of Letters Patent No. 600,347, dated March 8, 1898. Application filed December 9, 1896. Serial No. 615,034. (No specimens.) Patented in England April 16, 1896,1T0. 8,064.

To all whom it may concern.-

Be it known that we, THOMAS HUNTING- TON, a citizen of the United States of America, and FERDINAND HEBERLEIN, a subject of the German Emperor, residing at Pertusola, near Spezzia, in the Kingdom of Italy, have invented new and useful Improvements in the Treatment of Sulfid Ores of Lead for the Purpose of Desulfurizing the Same Preparatory to Smelting, (for which a patent has been granted in Great Britain, No. 8,064, dated April 16, 1896,) of which the following is a specification.

This invention relates to the treatment of galena or lead suliid, with the object of removing the sulfur or the greater portion thereof prior to subjecting the ore to smelting or other reduction process, the excess of sulfur eliminated being collected as sulfurous acid and utilized in the manufacture of sulfuric acid or otherwise.

lVe have found that by steadily raising the temperature of a mixture of galena with the monoxid of an alkaline-earth metal, as calcium monoxid, to a bright-red heat, say 7 00 centigrade, and then allowing it to cool slowly to a dull-red heat, say about 500 centigrade, the oxid appears to yield nascent oxygen, which attacks the lead sulfid energetically to oxidize it and to convert part of it into oxid (PbO) and sulfate of lead, (PbSO,,) considerable heat being generated. At this point by forcing a strong current of air (which may have been previously heated) through the said mixture the operation of conversion becomes continuous ancl the heat is maintained at such a point that reaction takes place between the sulfids and sulfates, the oxygen acting upon the galena so long as any free sulfur remains in the mixture. Concentrated fumes of sulfurous acid are given off and the mixture gradually fuses to a mass of lead oxid in conjunction with the gangue matter of the ore treated. The product thus obtained may be treated in any known manner for the reduction of the metal.

lVe believe that when the temperature of a mixture of calcium oxid and galena is raised to a bright-red heat the monoxid (CaO) absorbs oxygen and forms calcium dioxid (Oa'.0,) and that on the reduction of the temperature to a dull-red heat decomposition takes place and the dioxid is reduced to monoxid, as this appears to be the most probable rationale, although further investigation may possibly show our theory to be erroneous.

Assuming the reactions which take place to be such as we suggest, the above-mentioned phases of the process are represented by the following formulze:

1, at 700 centigrade:

oao+o:oaoI,.

2, at 500 centigrade:

4OaO +PbS-:4CaO+PbS.O

3, at fusing-point: PbS+PbSO :2PbO+2S.O

lglos. 1 and 2 combined, oxygen being pres- In applying our invention to the treatment of sulfid of lead ore or galena we mix with the ore a certain quantity of calcium oxid proportionate to the sulfur present and subject the mixture in a reverberatory or other suitable furnace to a bright-red heat, say 700 centigrade. The mixture is then allowed to cool to a dull-red heat, say 500 centigrade, when the above reaction of calcium dioxid (OaO uponthe galena and the formation of sulfate of lead commences. At this stage the mixture is removed to a receptacle, wherein it is exposed to the action of a current of air,which is forced through the mass, considerable heat being evolved and sulfurous acid driven off, the mixture fusing and gradually settling down to a mass of oxid of lead with the gangue matters of the ore. It is then ready for fur ther treatment in a blast-furnace or otherwise for the reduction of the metal.

While we have specified calcium monoxid as the preferred oxid of an alkaline-earth metal to be employed in carrying out our proc* ess, we Wish it understood that We include and may employ such known equivalent oxids of alkaline-earth metals as will produce the result sought.

Having thus described our invention, we claim- 1. The herein-described method of oxidizing sulfid ores of lead preparatory to reduction to metal, which consists in mixing with the ore to betreated an oxid of an alkalineearth metal, such as calcium oxid, subjecting the mixture to heat in the presence of air, then reducing the temperature and finally passing air through the mass to complete the oxidation of the lead, substantially as and for the purpose set forth.

2. The herein-described method of oxidizing sulfid ores of lead preparatory to reduction to metal, which consists in mixing calciuin-oxid or other oxid of an alkaline-earth metal with the ore to be treated, subjecting the mixture in the presence of air to a brightred heat (about 700 centigrade), then cooling as set forth.

THOMAS HUNTINGTON. FERDINAND HEBERLEIN. l/Vitnessesz ERNEST G. TAYLOR, W. F. CAIN. 

